Imaging detectors, such as focal plane arrays, generally include an array of pixels, each pixel including a photo-detector that generates a signal responsive to light generated or reflected by an object. These signals are collected and combined such that a digital image of the object can be created. Pixelated filter arrays positioned in a fixed location over the detector array are widely used in commercial imaging systems to provide hyperspectral or polarimetric capability. For example, digital cameras use fixed-in-place pixelated filter arrays for color (RGB) photography. However, these filters reduce the amount of light that reaches the imaging pixel (for example, a red filter reflects blue and green light). Polarimeters can be used to analyze the polarization components of light. Some polarimeters use two or more linear polarizers that filter at least half of the incoming light and direct the remaining light to a focal plane. As a result, the brightness of the image at the focal plane is substantially reduced (e.g., by about half).
U.S. Pat. No. 8,049,889 describes a switchable imaging polarimeter in which the device can operate in “polarimeter” or “non-polarimeter” modes. In the polarimeter mode, the system uses non-pixelated polarization filters to obtain polarimetric information about a scene, which reduces the system transmittance. In the non-polarimeter mode, the system does no polarization filtering and has high transmittance. The system switches between modes using an electro-optic switch. U.S. Pat. No. 6,226,460 describes a movable filter device that uses a mechanical rotary swing arm to move the filters.